The present invention relates to an electric window dimming device, a window unit, a method for controlling an electric window dimming device, an aircraft as well as the utilization of the electric window dimming device in an aircraft.
Modern window technology may make it possible to equip aircraft windows in today's commercial aircraft with electrically operated window shades. This free adjustability by an electric window shade makes it possible for the passengers to adjust the light transmission of an aircraft window in accordance with personal preferences. Possible dimming devices for windows are, for example, electrically or electromechanically operated awnings or covering devices that may enable the passengers to cover a certain region of an aircraft window.
Modern window technology furthermore may make it possible to adjust the light transmission over the entire window pane by electrically obscurable window films or coatings. These window films may be based on LCD-technologies, electrochromic films, LC-films (liquid crystal) or SPD-films (suspended-particle devices). In this case, the passengers may be able to individually adjust the respectively desired light transmission of a window pane similar to the effect of sunglasses.
Electric dimming devices may be operated with electric energy obtained from the on-board network. However, certain safety guidelines in the aircraft industry may stipulate that it must also be possible to set or adjust the electric dimming devices to a transparent state in case of a power failure of the on-board network. Transparency may be ensured, in particular, for door windows or windows near doors, for example, in order to make it possible to identify a fire in front of the door.
Consequently, it may have to be possible to set electromechanical dimming devices to the transparent state or to adjust obscurable coating or film technologies to the transparent state in case a power failure occurs. In this respect, the utilization of obscurable film technology, particularly the SPD-technology, may be problematic because the devices may be set to the opaque state in case of a power failure. SPD-films therefore may require some energy in order to remain in the transparent state.
This is usually realized with batteries that are intended to ensure that the electric dimming devices may still be operated in case of a power failure. Consequently, it is important to constantly check the batteries with respect to their operability and, if so required, to replace the batteries.